OFFSET
1,1
COMMENTS
The computations were done without any assumptions on the form of d.
LINKS
Sameen Ahmed Khan, Table of n, a(n) for n = 1..10000
S. A. Khan, Primes in Geometric-Arithmetic Progression, arXiv preprint arXiv:1203.2083, 2012. - From N. J. A. Sloane, Sep 15 2012
EXAMPLE
d = 18 then {5, 5 + 1*18, 5 + 2*18, 5 + 3*18} = {5, 23, 41, 59}, which is 4 primes in arithmetic progression.
MATHEMATICA
t={}; Do[If[PrimeQ[{5, 5 + d, 5 + 2*d, 5 + 3*d}] == {True, True, True, True}, AppendTo[t, d]], {d, 3000}]; t
CROSSREFS
KEYWORD
nonn
AUTHOR
Sameen Ahmed Khan, Feb 03 2012
STATUS
approved